A vehicle designed as an electric vehicle may comprise several asynchronous machines as traction drive units. In order to assure the largest possible driving range for the vehicle, the asynchronous machines are operated with minimal losses, wherein a magnetic flux is adapted to a particular operating state or load state. If an operating state is changed, for example, when initiating a passing procedure or upon change in the load distribution between front and rear axle, the magnetic flux is adapted to a new target torque by a regulating system of the machine, so that losses of the asynchronous machines are kept to a minimum. A time curve for magnetizing and demagnetizing can be described by an exponential function. Asynchronous machines can be described by an exponential curve. A time constant, such as a rotor time constant, which is associated with this exponential curve is specific to the machine.
However, a certain amount of time is required for the magnetizing of the asynchronous machines. If a change in the operating state, i.e., in this case the torque, should occur as rapidly as possible, the magnetic flux required for this must already have been adjusted. But if the necessary magnetic flux is permanently set, the magnetization current necessary for this will cause needless losses for all other operating states. These unwanted losses and the desire for a short adjustment time for the torque thus produce a time conflict between the efficiency and the dynamics of the torque.
An asynchronous motor with a performance that is automatically adjustable to a load condition is known from the document CH 170 198 A.
The document DE 1 538 300 A1 describes a control device for maintaining a shaft of a servomotor in an adjustable angle position with a switch which can be actuated by a cam disc.
Document DE 103 18 246 A1 describes a method for controlling the movement of an armature of an electromagnetic actuator for activating a gas exchange value of an internal combustion engine for a motor vehicle.